In a support garment for a patient-worn energy delivery apparatus, a vest-type garment holds an electrode belt in contact with a wearer's ribcage. The garment includes a flap with button holes to permit buttoning in of energy transfer electrodes, thus constituting a wearable electrode system. Additionally, a holster contains the components of a wearable cardioverter defibrillator that are not in contact with the skin. The holster has an adjustment for waist, girth and vertical position of the defibrillator according to the personal preferences of the wearer. The support garment includes a vest-like chest garment and an inner layer which provides support for the defibrillator electrodes. A removable electrode harness is attachable to the support garment in order to accurately position the sensing electrodes on the body of the wearer and energy delivery electrodes for transfer of an electrode therapy pulse to the wearer of the garment. The chest garment includes adjustable shoulder straps and waist belt so that the support garment can accommodate any body size or shape.